Work machine

Abstract

To provide a working machine capable of easily determining the necessity of two arrangements and improving the efficiency of cargo handling work.SOLUTION: A work machine includes a holding part for lifting a cargo, a first sensor for detecting an amount related to a load of the cargo applied to the holding part, and a second sensor for detecting a relative position between the cargo and the holding part, and determines the necessity of two stage preparation on the basis of detection results of the first sensor and the second sensor.SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] The present invention relates to a work machine. [Background technology]

[0002] When a work machine such as a forklift removes an object from a shelf, it may perform an operation called two-stage removal. Two-stage removal is a process in which, if the object is placed at the back of the shelf, the machine first lifts the object and pulls it toward the front, and then picks it up again and removes it from the shelf. Patent Document 1 describes a device that performs an operation similar to two-stage removal unmanned. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2021-088424 Summary of the Invention [Problem to be solved by the invention]

[0004] When a load is in a lifting position that does not allow stable transport, it is preferable to perform a two-stage process. The lifting position refers to the position of the load on the forks. On the other hand, when a load is in a lifting position that allows stable transport, two-stage process is not necessary. However, it has not been easy to accurately determine whether or not two-stage process is preferable.

[0005] An object of the present invention is to provide a work machine that can easily determine whether or not a second setup is required, thereby improving the efficiency of loading and unloading operations. [Means for solving the problem]

[0006] The present invention provides a holding part for lifting a load; a first sensor that detects an amount related to the load of the load applied to the holding portion; a second sensor that detects the relative position between the load and the holding portion; Equipped with determining whether or not a second setup is necessary based on the detection results of the first sensor and the second sensor; It is a work machine. [Effects of the Invention]

[0007] According to the present invention, the necessity of two-stage preparation can be accurately determined, thereby improving the efficiency of cargo handling work. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a side view showing a work machine according to an embodiment of the present invention. [Figure 2] FIG. [Figure 3] 10 is a flowchart illustrating a procedure for a load removal process executed by a controller of the embodiment. [Figure 4] FIG. 4 is a load curve diagram showing the relationship between a load position and an allowable load. [Figure 5] 1A and 1B are diagrams showing a first state (A) and a second state (B) in which the determination results of whether or not two-stage setup is necessary are different. [Figure 6] 10A and 10B are diagrams showing a third state (A) and a fourth state (B) in which the determination results of whether or not two-stage setup is necessary are different. [Figure 7] 1 is a flowchart showing a two-stage procedure. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

[0010] Fig. 1 is a side view showing a working machine according to an embodiment of the present invention, and Fig. 2 is a plan view showing the working machine according to the embodiment.

[0011] The work machine 100 of this embodiment is a forklift that loads a load onto the forks 104 and handles the load (lifts and transports the load). The work machine 100 may also be called a load handling device. The forks 104 correspond to an example of a holding section according to the present invention.

[0012] The work machine 100 includes a body 102 including wheels 101 and a driver's seat 103, forks 104 having a pair of left and right claws extending forward of the body 102, a backrest 105 located behind the forks 104, and a fork drive mechanism 110 that drives the forks 104. The driver's seat 103 is provided with a travel operation unit 106a that performs driving operations related to the travel of the body 102, a fork operation unit 106b that performs driving operations for the forks 104, and a notification unit 107 that notifies the driver of driving assistance information.

[0013] The notification unit 107 is a display capable of outputting images, but may also be a lamp or a speaker capable of outputting audio.

[0014] The fork drive mechanism 110 is a mechanism that can raise and lower the forks 104 and the backrest 105 and change the tilt angle (i.e., the front-to-rear tilt angle). In addition, the fork drive mechanism 110 may include a mechanism that can slide the forks 104 and the backrest 105 laterally.

[0015] The fork drive mechanism 110 includes a base mast 111 attached to the vehicle body 102 so that its tilt angle can be changed, a tilt cylinder 116 that changes the tilt angle of the base mast 111, a lifting mast 112 attached to the base mast 111 so that it can be raised and lowered, a lifting cylinder 117 that raises and lowers the lifting mast 112, and a lift chain 113 and a mast roller 114 that raise and lower the fork 104 and backrest 105 in conjunction with the raising and lowering of the lifting mast 112.

[0016] The fork 104 and the backrest 105 are connected to a lifting frame 115, and the lifting frame 115 is guided by a lifting mast 112 so that it can move up and down. A mast roller 114 is attached to the lifting mast 112, and a lift chain 113 is hung between the mast roller 114. One end of the lift chain 113 is fixed to a base of the base mast 111 or the like, and the other end is fixed to the lifting frame 115.

[0017] The tilt cylinder 116 is a piston cylinder driven by fluid pressure (e.g., hydraulic pressure). When hydraulic fluid is supplied to the tilt cylinder 116, the piston rod 116a is pushed out, and the tilt angle of the forks 104 and backrest 105 changes so that the tips of the forks 104 rise. Conversely, when hydraulic fluid is removed from the tilt cylinder 116, the piston rod 116a is pulled back, and the tilt angle of the forks 104 and backrest 105 changes so that the tips of the forks 104 fall. A moment load is applied to the piston rod 116a of the tilt cylinder 116, with the center of the tilt angle of the forks 104 serving as the center of rotation. The tilt cylinder 116, the piston rod 116a, the parts connecting these to the structure of the work machine 100, and the configuration that supplies the hydraulic fluid to the tilt cylinder 116 correspond to the tilt drive unit according to the present invention.

[0018] The lift cylinder 117 is a piston cylinder driven by fluid pressure (e.g., hydraulic pressure). When hydraulic fluid is supplied to the lift cylinder 117, the piston rod 117a is pushed out, and the lift mast 112 and mast roller 114 are raised. This raising applies tension to the lift chain 113 hung on the mast roller 114, which pulls up the lift frame 115. This action raises the fork 104 and backrest 105. Conversely, when hydraulic fluid is removed from the lift cylinder 117, the piston rod 117a is pulled back, and the lift mast 112 and mast roller 114 are lowered. This pulls down the lift frame 115 suspended by the lift chain 113. This action lowers the fork 104 and backrest 105.

[0019] The work machine 100 further includes a load sensor (corresponding to an example of a first sensor) 121 that detects the amount of load applied to the fork 104, a camera (corresponding to an example of a second sensor) 122 that detects the relative position between the load and the fork 104, and a controller 130 that determines whether or not a second setup is required based on the outputs of the load sensor 121 and the camera 122.

[0020] In this embodiment, as shown in Figures 5 to 7, a configuration that combines a pallet 201 and a load 202 placed on the pallet 201 is applied as the "load" according to the present invention. Note that a configuration of only the load 202, omitting the pallet 201, may also be applied as the "load" according to the present invention. The pallet 201 is a loading / unloading member that has a base surface on which the load is placed and insertion holes into which the forks 104 can be inserted, and can be lifted by the work machine 100.

[0021] The load sensor 121 is, for example, a piezoelectric element provided on the piston rod 116a of the tilt cylinder 116. With this configuration, the load sensor 121 can detect the moment load in the tilt angle direction applied to the fork 104 as a quantity related to the load of the load. As shown in FIG. 2, the load sensor 121 may be provided on each of the piston rods 116a of the two tilt cylinders 116, one on the left and one on the right. With this configuration, it becomes possible to compare the magnitude of the moment load applied to the left side of the fork 104 and the magnitude of the moment load applied to the right side of the fork 104.

[0022] The first sensor that detects the amount of load applied to the fork 104 is not limited to the load sensor 121. The first sensor may be any configuration that can directly or indirectly detect the load or moment load of the load, such as a sensor that detects the tension applied to the lift chain 113, a piezoelectric element provided on the piston rod 117a of the lift cylinder 117, or a hydraulic pressure sensor that detects the hydraulic pressure of the hydraulic fluid in the tilt cylinder 116 or the lift cylinder 117. The load can be roughly calculated based on the moment load and the above-mentioned relative position, and the moment load can be roughly calculated based on the load and the above-mentioned relative position. Therefore, whether the first sensor detects a load or a moment load, similar information can be obtained.

[0023] The camera 122 photographs the fork 104 from above or below, thereby detecting how far the fork 104 is inserted into the pallet 201 (see FIG. 7) and how far it is not inserted into the pallet 201 (hereinafter, the length of the part that is not inserted is referred to as "insertion distance L1"; see FIG. 5(A)). The controller 130 may perform image recognition processing based on the photographed image to calculate the insertion distance.

[0024] The second sensor that detects the relative position between the load and the forks 104 is not limited to the camera 122. The second sensor may be, for example, an RGBD (RGB Depth) camera that can acquire pixel data and depth data for each point in a field of view, or a 3D-LiDAR (light detection and ranging) that can measure a three-dimensional shape by scanning detection points in two dimensions. Even in this configuration, the relative position between the pallet 201 and the forks 104 can be detected by similar imaging. The second sensor that detects the relative position between the load and the forks 104 may also be configured to detect the relative position between the load 202 and the forks 104. The second sensor is not limited to a configuration that photographs or scans the forks 104 from above or below, and may be, for example, a distance measuring sensor that detects the distance from the base of the forks 104 to the side of the pallet 201 or the load 202 on it. The distance measuring sensor may be, for example, an RFID (Radio Frequency Identification) that measures distance based on radio wave intensity, or a TOF (Time of Flight) reflective laser sensor.

[0025] The output of the load sensor 121 and the output of the camera 122 are sent to a controller 130 .

[0026] The controller 130 is a computing device that operates according to a control program stored in the memory unit 130a, and is configured to be able to control the travel of the work machine 100 and the drive of the forks 104. The controller 130 can automatically operate the work machine 100 by performing the above-mentioned travel control and drive control.

[0027] Note that instead of automatic driving, the controller 130 may be configured to provide driving assistance to the operator of the work machine 100. Driving assistance may be a process of outputting driving assistance information via the notification unit 107, or may be a process of performing a part of the driving operation of the work machine 100, such as driving to pick up a load. The driving assistance information may include information instructing movements such as raising and lowering the forks 104, and moving the work machine 100 forward and backward, information on the need for two-stage setup, etc.

[0028] <Loading process> 3 is a flowchart showing the procedure of the article unloading process executed by the controller of the embodiment. In the following, an example of the article unloading process being executed during automatic operation by the controller 130 will be shown.

[0029] The load unloading process begins when the work machine 100 unloads a load from a storage platform (such as a truck bed or a shelf) at the transport source. The load is placed on a pallet 201. When this process begins, the controller 130 first inserts the forks 104 into the target pallet 201 and raises the forks 104 to lift the pallet 201 and the load 202 (step S1). Here, the pallet 201 is slightly floating above the storage platform.

[0030] Next, the controller 130 takes in the outputs of the load sensor 121 and the camera 122 and measures the load (specifically, the moment load) applied to the fork 104 and the insertion distance L1 of the fork 104 into the pallet 201 (step S2). The insertion distance L1 indicates the distance from the base P1 of the fork 104 to the front end of the pallet 201, as shown in Figures 5(A) and 5(B). Therefore, the insertion distance L1 takes a small value when the fork 104 is deeply inserted into the pallet 201, and takes a large value when the fork 104 is shallowly inserted into the pallet 201.

[0031] Next, the controller 130 determines whether or not there is an abnormality in the load applied to the forks 104 (step S3). An abnormality in the load can be, for example, when the imbalance in the load between the left and right sides of the forks 104 is equal to or greater than a threshold value. If the determination in step S3 indicates an abnormality in the load, the controller 130 terminates the load removal process due to the occurrence of an abnormality. On the other hand, if there is no abnormality in the load, the controller 130 then determines whether or not a second setup is required (step S4).

[0032] <<Determining whether or not two-stage work is necessary>> Fig. 4 is a diagram of a load curve showing the relationship between the load position and the allowable load. Fig. 5 is a diagram showing a first state (A) and a second state (B) in which the determination results of whether or not two-stage setup is necessary are different. Fig. 6 is a diagram showing a third state (A) and a fourth state (B) in which the determination results of whether or not two-stage setup is necessary are different.

[0033] The memory unit 130a of the controller 130 stores data of the load curve shown in FIG. 4. The load curve in FIG. 4 shows the relationship between the load center and the allowable load. The load center above represents the distance in the front-to-rear direction from the center of the load applied from the load 202 to the fork 104 to a specified position of the fork 104 (for example, the base P1; see FIG. 5(A)). The allowable load represents the weight of a load that can be handled stably. As shown in the load curve, the allowable load decreases as the load center is positioned closer to the tip of the fork 104.

[0034] In determining whether two-stage setup is required (step S4), the controller 130 first calculates the allowable load corresponding to the insertion distance L1 based on the insertion distance L1 of the fork 104 measured in step S2 and the load curve data. The allowable load corresponding to the insertion distance L1 means the allowable load when the load center is located at the center of the pallet 201 at the insertion distance L1. Therefore, the controller 130 first calculates how far forward the center of the pallet 201 is from the specified position P1 of the fork 104 based on the insertion distance L1 and the dimensional data of the pallet 201. Next, by comparing this position with the load curve data, the controller 130 calculates the allowable load corresponding to this position as the allowable load corresponding to the insertion distance L1.

[0035] In determining whether two-stage setup is necessary (step S4), the controller 130 then compares the load measured in step S2 with the allowable load corresponding to the insertion distance L1, and determines that two-stage setup is necessary if the former is greater, and determines that two-stage setup is not necessary if the latter is greater. Since the measurement value of the load sensor 121 in step S2 is a moment load, the controller 130 converts the moment load into a load, assuming that the center of the load is on the pallet 201, and performs the above comparison. Note that the "allowable load" used in the above comparison may be replaced with "α × allowable load" by multiplying it by a weighting coefficient α to increase or decrease the margin.

[0036] 5(A) and (B), it is assumed that the load 202 is located at the center of the pallet 201 and the weight of the load 202 is close to the allowable load at the center position P2 of the forks 104. In this assumption, if the insertion distance L1 is small, as shown in FIG. 5(A), stable loading is possible, whereas if the insertion distance L1 is large, as shown in FIG. 5(B), stable loading becomes difficult. The calculation process of step S4 determines whether or not two-stage loading is necessary depending on whether or not stable loading can be achieved.

[0037] Next, assume that the loading position of the load 202 is shifted in the front-to-rear direction of the pallet 201, as shown in Figures 6(A) and (B). In this assumption, even if the insertion distance L1 is the same, stable loading may be difficult depending on the weight of the load 202 when the load 202 is shifted forward as in Figure 6(A). On the other hand, stable loading may be possible when the load 202 is shifted backward as in Figure 6(B). This difference is reflected in the load measurement result in step S2, such that the value of the load sensor 121 is large in the former case and the value of the load sensor 121 is small in the latter case. Then, by performing the calculation process in step S4 using the value of the load sensor 121, a determination result as to whether or not two-stage loading is necessary is obtained depending on whether or not stable loading can be performed.

[0038] The flow chart of Figure 3 will be continued. If the result of determining whether or not a second setup is required in step S4 is that it is not required, the controller 130 does not perform the second setup and carries out the process of removing the load 202 while maintaining the insertion distance L1 at that time (step S6). In the process of removing the load 202, the controller 130 moves the load 202 out of the storage platform at the storage location, for example, by moving the work machine 100 backward while lifting the load 202 together with the pallet 201 from the storage platform at the transportation source. Next, the controller 130 lowers the fork 104, thereby putting the pallet 201 and the load 202 into a transportation state, and the process of removing the load 202 is completed.

[0039] On the other hand, if the result of determining whether or not a second setup is necessary in step S4 indicates that it is necessary, the controller 130 executes the second setup process (step S5). FIG. 7 is a flow chart showing an example of the procedure for the second setup. The second setup process can occur when the pallet 201 and the load 202 are located deep inside the storage platform 300, as shown in step J1 in FIG. 7. At the stage of the necessity determination process in step S4, the pallet 201 and the load 202 are slightly floating above the storage platform 300, as shown in step J2. When the second setup process in step S5 is started in this state, the controller 130 first moves the work machine 100 backward a distance corresponding to the insertion distance L1 (step J3), and then lowers the forks 104 to lower the pallet 201 and the load 202 onto the storage platform 300 (step J4). As a result, the pallet 201 and the load 202 move forward of the storage platform 300. Next, the controller 130 moves the work machine 100 forward to insert the forks 104 all the way into the pallet 201 (step J5), and then raises the forks 104 to lift the pallet 201 and load 202 off the storage platform 300 (step J6). This completes the second setup. Then, the controller 130 moves the work machine 100 backward to remove the load 202 and pallet 201 from the storage platform 300 (step J7 in FIG. 7: step S6 in FIG. 3).

[0040] When the pallet 201 and the cargo 202 are removed from the storage platform 300 in step S6 of FIG. 3, the controller 130 then shifts the process to a transportation process (not shown).

[0041] According to the above-described unloading process, the load 202 is pre-staged when stable transportation is difficult without pre-staged transportation, while unnecessary pre-staged transportation is suppressed when stable transportation is possible without pre-staged transportation. Therefore, efficient unloading and transportation of the load 202 can be realized.

[0042] As described above, the work machine 100 of this embodiment is equipped with the forks 104 that lift the load (pallet 201 and load 202), the load sensor 121 that detects the amount of load applied to the forks 104, and the camera 122 that detects the relative position of the load and the forks 104. The controller 130 then determines whether or not two-stage setup is required based on the output of the load sensor 121 and the output of the camera 122 (step S4 in FIG. 3). Therefore, an accurate determination result as to whether or not two-stage setup is required can be easily obtained, enabling stable and efficient load handling processing.

[0043] Furthermore, according to the work machine 100 of this embodiment, the controller 130 determines whether an abnormality has occurred based on the imbalance in the load in the left-right direction applied to the forks 104 (step S3 in FIG. 3). Therefore, more stable cargo handling can be achieved.

[0044] Furthermore, according to the work machine 100 of this embodiment, the load sensor 121, which detects the amount of load related to the load of the load, is provided on the piston rod 116a of the tilt cylinder 116, and the load sensor 121 detects the moment load in the tilt angle direction. Therefore, even in situations where the position of the load 202 relative to the pallet 201 varies widely as shown in Figures 6(A) and 6(B), the difference in the position of the load 202 is reflected in the detection value of the load sensor 121. Therefore, it is possible to accurately determine whether or not a second setup is required without detecting the relative position of the load 202 itself.

[0045] Furthermore, according to the work machine 100 of this embodiment, the insertion distance L1 of the forks 104 into the pallet 201 is detected as the relative position between the forks 104 and the load (pallet 201 and cargo 202). Therefore, the relative position can be detected easily and accurately, and the calculation for determining whether or not a second setup is required can be simplified, eliminating the need for complex determination processing.

[0046] The above describes an embodiment of the present invention. However, the present invention is not limited to the above embodiment. For example, in the above embodiment, forks 104 were shown as a holding unit for lifting a load. However, any element capable of holding and lifting a load, such as a robotic hand of a work robot that lifts a load, such as a manipulator, may be used. Furthermore, in the above embodiment, an example was shown in which the load curve in FIG. 4 was used to determine whether a load needs to be transported twice. However, the determination of whether a load needs to be transported twice may be made by calculating whether stable transport of the load is possible from the measured load and relative position, without using the load curve. Furthermore, in the above embodiment, a configuration was shown in which the work machine 100 includes a controller 130 that performs arithmetic processing for determining whether a load needs to be transported twice. However, this arithmetic processing itself may be performed by a computer external to the work machine 100. Furthermore, in the above embodiment, an example was shown in which the load unloading process, including the determination of whether a load needs to be transported twice, is performed automatically by the work machine 100. However, the work machine 100 may output driving assistance information to the driver to provide driving assistance so that the driver can perform a similar operation instead of the automatic driving. In addition, the details shown in the embodiments can be modified as appropriate without departing from the spirit of the invention. [Explanation of symbols]

[0047] 100 Work Machinery 102 Body 104 Fork (holding part) 121 Load sensor (first sensor) 122 Camera (Second Sensor) 116 Tilt cylinder (tilt drive unit) 116a Piston rod (tilt drive part) 130 Controller 201 Pallet (load) 202 Cargo (load) L1 Insertion distance

Claims

1. a holding part for lifting a load; a first sensor that detects an amount related to the load of the load applied to the holding portion; a second sensor that detects the relative position between the load and the holding portion; Equipped with determining whether or not a second setup is necessary based on the detection results of the first sensor and the second sensor; Work machinery.

2. 2. The working machine according to claim 1, further comprising: a step of determining whether an abnormality has occurred based on a bias in the load applied to the holding portion in the left-right direction.

3. a tilt drive unit that drives the holding unit in a tilt angle direction, The first sensor is provided in the tilt drive unit. The work machine according to claim 1.

4. The second sensor detects an insertion distance of the holder into a pallet on which a load is placed. The work machine according to claim 1.

Images